Jutt on siis sellest, kes akvaariumifiltris tööd teevad.
Reinu tsitaadi allikas on
http://www.aquaria.info/index.php?name= ... me=PrinterRein kirjutas:
See on kahtlemata huvitav teooria - kuid seni siiski vaid teooria sest tundub et see on vaid ühe mehe nägemus asjast, ma ei kiirustaks selle alusel põhjapanevate järeldustega.
For years it was believed that the species of bacteria responsible for nitrification were Nitrobacter and Nitrosomonas. It has recently been shown that this is wrong and that Nitrospira is actually responsible.
Levinum ja üldtunnustatud arusaam on siiski selline et Nitrosomonas oksüdeerib ammoniaagi nitritiks ning Nitrospira või Nitrobacteri rolliks on nitriti oksüdeerimine nitraatideks. Selle kohta leiab hulgi ka autoriteetseid allikaid.
See originaaltekst, mida Rein tsiteeris, on tõesti kehv (poolik) ning autor oleks pidanud konkreetsemalt kirjutama nii, et kõik aru saavad. Tundub, et ta lause jäi poolikuks. Kahjuks ei selgu, kes oli selle teksti autor.
Mõte on see, et Reinu toodud levinum ja üldtunnustatud versioon ei ole siiski korrektne.
Nitrobacter on akvaristikas tähtsusetu tegija ning ka Nitrosomonas bakterite roll ei ole nii domineeriv.
Kood:
Magevees käib asi nii:
Nitrosomonas marina-like and Nitrosospira NH3 -> NO2
Nitrospira-like NO2 -> NO3
Merevees käib asi nii:
Nitrosomonas aestuarii-like and N. halophila-like NH3 -> NO2
Nitrospira marina-like NO2 -> NO3
Vaadake 2004 powerpoint presentatsiooni:
http://aqualitysymposium.org/ppts/biolo ... cteria.ppthttp://www.marineland.com/science/biosp ... ospira.aspTimothy A. Hovanec, Ph.D. kirjutas:
I then did an experiment were I took nucleic acids from many aquarium set-ups, including freshwater, saltwater, with fish in the tanks, tanks which were dosed with ammonium chloride, heavily and lightly stocked tanks, and probed them with the molecular probes for both Nitrobacter and Nitrospira. The results were that in no case did I find Nitrobacter (same results as in my earlier paper) but in every freshwater aquarium I found Nitrospira and in each saltwater aquaria I found evidence of Nitrospira. Thus, I am able to conclude that Nitrobacter and its close relatives are not the nitrite-oxidizing bacteria in aquarium filters and that Nitrospira-like bacteria are present in the filters.
http://www.marineland.com/science/biosp ... OxBact.aspTimothy A. Hovanec, Ph.D. kirjutas:
However, some people in the fish hobby business have misinterpreted my paper and are saying that I found that Nitrosomonas europaea does not oxidize ammonia and, by the way, that Nitrobacter winogradskyi does not nitrite. These statements are wrong and are not what I found. Nitrosomonas europaea does oxidize ammonia and Nitrobacter winogradskyi does oxidize nitrite but they don't seem to be present in freshwater aquaria. Further, some people think that I was just plain wrong but that's another story.
So why is it assumed that the ammonia-oxidizer is Nitrosomonas europaea? Because, among other things, that's the bacteria which is believed to oxidize ammonia in wastewater treatment plants. The problems with this thinking it that just because a bacterium in found in one environment which contains the substrate it prefers does not mean it would be automatically found in another environment which also has that substrate. Secondly, no one has proven that N. europaea is really the major ammonia-oxidizer in wastewater facilities. In fact, recent studies has shown that while N. europaea can be found in the microbial assemblage of wastewater plants, they may not be the dominant ammonia-oxidizer.
Timothy A. Hovanec kirjutas:
It's time for hobbyists, technical people, and writers of articles in the fish hobby press to start using the correct name for the nitrite-oxidizing bacteria in aquaria - Nitrospira.
Timothy A. Hovanec tundub olevat autoriteetne tegelane.
http://lib.bioinfo.pl/auth:Hovanec,TAIdentification of Bacteria Responsible for Ammonia Oxidation in Freshwater Aquaria
http://aem.asm.org/cgi/content/full/67/12/5791Tsiteeri:
When ammonia concentrations were varied, AOB population shifts did occur, thereby altering the presence and activity of important AOB. Low-ammonia environments will likely produce Nitrosomonas marina-like AOB, while as the ammonia concentration increases, Nitrosospira tenuis-like and Nitrosomonas europaea-like AOB will become important until at the highest ammonia concentration Nitrosococcus mobilis-like AOB may be predominant. Our results suggest that the AOB found in fish culture environments, such as public aquaria, aquaculture facilities, and home aquaria, where the ambient ammonia concentration rarely exceeds 5 mg of N per liter, are different from the traditional Nitrosomonas europaea-Nitrosococcus mobilis cluster type AOB, which are prevalent in the high-ammonia concentrations typically found in environment such as wastewater and sewage treatment facilities. This, and our results with enrichments of the various strains of AOB in newly set-up aquaria, strongly suggest that start-up inocula for the establishment of nitrification in aquatic culture systems should optimally consist of Nitrosomonas marina-like AOB rather than Nitrosomonas europaea-Nitrosococcus mobilis cluster AOB.
Veel viiteid:
http://microbewiki.kenyon.edu/index.php/NitrospiraTsiteeri:
In addition, Nitrospira-like bacteria are the main nitrite oxidizers in wastewater treatment plants and in laboratory scale reactors, not Nitrobacter sp., as was previously thought.
Tsiteeri:
Nitrification is the oxidation of ammonia to nitrite by autotrophic bacteria of the genus Nitrosomonas and oxidation of the nitrite to nitrate by bacteria in the genus Nitrobacter or Nitrospira.
Tsiteeri:
Thus, Nitrospira is now considered the dominate nitrite-oxidizing bacterium in aquariums, (as well as in wastewater treatment systems and other reactors as shown by other similar studies) (Hovanec et al.1998). Though water that is too rich in ammonia or has a pH that is too low will inhibit Nitrospira's nitrifying activity.
http://www.microbial-ecology.net/nitriteoxidizers.aspTsiteeri:
Only recently, cultivation-independent methods revealed that novel, yet uncultured NOB are far more important than Nitrobacter in wastewater treatment plants (Burrell et al., 1998; Juretschko et al., 1998; Schramm et al., 1998). These bacteria belong to the genus Nitrospira, which is part of the bacterial phylum Nitrospirae (Ehrich et al., 1995), and are not related to Nitrobacter.
NB! Viide teistele teadlastele, seega tegemist ei ole ühe inimese nägemusega.
http://www.marineland.com/science/nspira.aspTsiteeri:
Molecular research is impacting all facets of our lives. Yet, until recently, this research had only scratched the surface of the aquatic industry. Now, however, using the modern methods of molecular biology including bacterial cloning, DNA sequencing, DNA fingerprinting, and Fluorescent In Situ Hybridization Marineland Labs has discovered BIO-Spira, the actual bacteria responsible for nitrification in closed aquatic systems.
Põhijutt on Nitrospira versus Nitrobacteria, mis on mõlemad teise faasi osalised ehk nitraatide tootjad.
http://www.microbial-ecology.net/nitriteoxidizers.aspTsiteeri:
Nitrite-oxidizing bacteria (NOB) catalyze the second step of aerobic nitrification, the oxidation of nitrite (NO2-) to nitrate (NO3-).
http://www.marineland.com/science/biosp ... acter2.aspTeised teadlased on samuti uurinud: Burrell, P. C., J. Keller, and L. L. Blackall.
http://www.flippersandfins.net/CyclingB ... cteria.htmNeed algajad, kes on üritanud oma filtris Nitrobacteria baktereid kasvatada, võivad kergendusega hingata, et ebaõnnestumine polnud nende süü. Oleks tulnud keskenduda teistele bakteritele
Need, kes leiavad oma filtrist Nitrosomonas europaea baktereid, peavad tõdema et tegemist pole akvaariumiga vaid kõrge ammoniaagikontsentratsiooniga solgiveekaevuga
EDIT: no on ikka tähevigu
Otsi
Postitatud: Esmaspäev Veebr 19, 2007 05:02 